fix(ecs): don't seed lastSentData from incoming CRDT updates

Author: nicoecheza

packages/@dcl/ecs/src/engine/lww-element-set-component-definition.ts

@@ -171,7 +171,10 @@ export function createUpdateLwwFromCrdt(
         if (msg.type === CrdtMessageType.PUT_COMPONENT || msg.type === CrdtMessageType.PUT_COMPONENT_NETWORK) {
           const buf = new ReadWriteByteBuffer(msg.data!)
           data.set(entity, schema.deserialize(buf))
-          lastSentData.set(entity, new Uint8Array(msg.data!))
+          // do NOT seed lastSentData from an INCOMING message!!!!
+          // seeding it from received bytes makes the engine
+          // believe it already sent this state, which kills valid re-broadcasting 🧨
+          lastSentData.delete(entity)
         } else {
           data.delete(entity)
           lastSentData.delete(entity)

test/ecs/crdt-unchanged-mutable.spec.ts

@@ -1,6 +1,10 @@
 import { Engine, Entity } from '../../packages/@dcl/ecs/src/engine'
 import { Schemas } from '../../packages/@dcl/ecs/src/schemas'
-import { CrdtMessageType, PutComponentMessageBody, DeleteComponentMessageBody } from '../../packages/@dcl/ecs/src/serialization/crdt/types'
+import {
+  CrdtMessageType,
+  PutComponentMessageBody,
+  DeleteComponentMessageBody
+} from '../../packages/@dcl/ecs/src/serialization/crdt/types'
 import { ReadWriteByteBuffer } from '../../packages/@dcl/ecs/src/serialization/ByteBuffer'
 
 const PositionSchema = {
@@ -146,7 +150,7 @@ describe('CRDT message suppression for unchanged mutables', () => {
     expect((changeMessages[0] as PutComponentMessageBody).timestamp).toBe(2)
   })
 
-  it('should update snapshot after receiving remote CRDT update', () => {
+  it('should re-emit local state after receiving a remote CRDT update', () => {
     const engine = Engine()
     const entity = engine.addEntity()
     const Position = engine.defineComponent('position-test-7', PositionSchema)
@@ -167,10 +171,10 @@ describe('CRDT message suppression for unchanged mutables', () => {
       timestamp: 10
     })
 
-    // getMutable without change after remote update
     Position.getMutable(entity)
     const messages = Array.from(Position.getCrdtUpdates())
-    expect(messages).toHaveLength(0)
+    expect(messages).toHaveLength(1)
+    expect(messages[0].type).toBe(CrdtMessageType.PUT_COMPONENT)
   })
 
   it('should correctly handle multiple getMutable calls per tick', () => {

test/ecs/customComponent.spec.ts

@@ -278,7 +278,7 @@ describe('test CRDT flow E2E', () => {
           componentId: int8A.componentId,
           entityId: entityA,
           type: CrdtMessageType.DELETE_COMPONENT,
-          timestamp: 6
+          timestamp: 7
         },
         {
           direction: 'a->b',